Methods for manufacturing wind turbine rotor blades and components thereof

ABSTRACT

The present disclosure is directed to methods for manufacturing wind turbine rotor blades and components thereof. In one embodiment, the method includes forming an outer surface of a rotor blade panel from one or more fiber-reinforced outer skins. The method also includes printing and depositing at least one reinforcement structure onto an inner surface of the one or more fiber-reinforced outer skins to form the rotor blade panel, wherein the reinforcement structure bonds to the one or more fiber-reinforced outer skins as the reinforcement structure is being deposited.

PRIORITY CLAIM

The present application is a continuation of U.S. application Ser. No.15/424,055 having a filing date of Feb. 3, 2017. Applicant claimspriority to and the benefit of such application and incorporates suchapplication herein by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates in general to wind turbine rotor blades,and more particularly to methods of manufacturing wind turbine rotorblades and components thereof.

BACKGROUND OF THE INVENTION

Wind power is considered one of the cleanest, most environmentallyfriendly energy sources presently available, and wind turbines havegained increased attention in this regard. A modern wind turbinetypically includes a tower, a generator, a gearbox, a nacelle, and oneor more rotor blades. The rotor blades capture kinetic energy of windusing known foil principles. The rotor blades transmit the kineticenergy in the form of rotational energy so as to turn a shaft couplingthe rotor blades to a gearbox, or if a gearbox is not used, directly tothe generator. The generator then converts the mechanical energy toelectrical energy that may be deployed to a utility grid.

The rotor blades generally include a suction side shell and a pressureside shell typically formed using molding processes that are bondedtogether at bond lines along the leading and trailing edges of theblade. Further, the pressure and suction shells are relativelylightweight and have structural properties (e.g., stiffness, bucklingresistance and strength) which are not configured to withstand thebending moments and other loads exerted on the rotor blade duringoperation. Thus, to increase the stiffness, buckling resistance andstrength of the rotor blade, the body shell is typically reinforcedusing one or more structural components (e.g. opposing spar caps with ashear web configured therebetween) that engage the inner pressure andsuction side surfaces of the shell halves. The spar caps are typicallyconstructed of various materials, including but not limited to glassfiber laminate composites and/or carbon fiber laminate composites. Theshell of the rotor blade is generally built around the spar caps of theblade by stacking layers of fiber fabrics in a shell mold. The layersare then typically infused together, e.g. with a thermoset resin.

Conventional blade manufacturing of large rotor blades involve highlabor costs, slow through put, and low utilization of expensive moldtooling. Further, the blade molds can be expensive to customize.

Thus, methods for manufacturing rotor blades may include forming therotor blades in segments. The blade segments may then be assembled toform the rotor blade. For example, some modern rotor blades, such asthose blades described in U.S. patent application Ser. No. 14/753,137filed Jun. 29, 2015 and entitled “Modular Wind Turbine Rotor Blades andMethods of Assembling Same,” which is incorporated herein by referencein its entirety, have a modular panel configuration. Thus, the variousblade components of the modular blade can be constructed of varyingmaterials based on the function and/or location of the blade component.

Thus, the art is continually seeking methods of manufacturing windturbine rotor blades and components thereof.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one aspect, the present disclosure is directed to a method formanufacturing a rotor blade of a wind turbine. The method includesforming a rotor blade structure having a first surface and an opposing,second surface, the first and second surfaces being substantially flat.Another step includes printing, via a computer numeric control (CNC)device, a leading edge segment of the rotor blade onto the firstsurface, wherein the leading edge segment bonds to the first surface asthe leading edge segment is being deposited. Further, the methodincludes rotating the rotor blade structure having the leading edgesegment attached thereto, e.g. until the opposing second surface isfacing upward. Thus, the method also includes printing, via the CNCdevice, a trailing edge segment of the rotor blade onto the secondsurface, wherein the leading edge segment bonds to the first surface asthe leading edge segment is being deposited. In addition, the methodincludes securing one or more fiber-reinforced outer skins to theprinted leading and trailing edge segments so as to complete the rotorblade.

In one embodiment, the rotor blade structure may include at least one ofa shear web or one or more spar caps. Further, in certain embodiments,the step of forming the rotor blade structure may include forming theshear web from one or more sandwich panels having a core materialsurrounded by one or more fiber-reinforced thermoplastic or thermosetskins. In addition, the step of forming the rotor blade structure mayinclude machining, water-jet cutting, or laser-jet cutting a profile ofthe shear web into the sandwich panel. In particular embodiments, theshear web and the one or more spar caps may include a box configuration.

In another embodiment, the method may further include forming one ormore slots in at least one of the rotor blade structure, the leadingedge segment, or the trailing edge segment, inserting the one or morespar caps into the one or more slots, and securing the one or more sparcaps into the one or more slots via at least one of adhesives,fasteners, or welding.

In further embodiments, the leading and trailing edge segments of therotor blade may be constructed of a fiber-reinforced thermoplastic orthermoset material.

In additional embodiments, the step of rotating the rotor bladestructure having the leading edge segment attached thereto may includeutilizing a fourth axis configured in the CNC device that rotates therotor blade structure.

In another embodiment, the step of securing one or more fiber-reinforcedouter skins to the leading and trailing edge segments so as to completethe rotor blade may include at least one of bonding or welding the oneor more fiber-reinforced thermoplastic or thermoset outer skins to theleading and trailing edge segments.

In certain embodiments, the fiber-reinforced outer skin(s) may includecontinuous, multi-axial fibers, such as biaxial fibers. In furtherembodiments, the fiber-reinforced outer skin(s) may include pressure andsuction side skins, a split trailing edge segment skin, leading andtrailing edge segment skins, or combinations thereof.

In yet another embodiment, the method may include forming thefiber-reinforced outer skin(s) via at least one of injection molding,three-dimensional (3-D) printing, two-dimensional (2-D) pultrusion, 3-Dpultrusion, thermoforming, vacuum forming, pressure forming, bladderforming, automated fiber deposition, automated fiber tape deposition, orvacuum infusion.

In additional embodiments, the method may further include printing, viathe CNC device, one or more structural components at one or morelocations of the rotor blade containing a gap. In such embodiments, theone or more locations may include at least one of the leading edgesegment, the trailing edge segment, or the spar caps of the rotor blade.

In still further embodiments, the method includes securing one or morefiber-reinforced inner skins to the rotor blade structure prior toprinting the leading and trailing edge segments.

In another embodiment, the method includes printing, via the CNC device,one or more additional features directly to the rotor blade structure,wherein heat from the printing bonds the additional features to therotor blade structure. More specifically, in certain embodiments, theadditional feature(s) may include a structural shear clip, a lightningcable connection guide, a lightning cable cover, a gusset feature, alanding interface, a trough for the one or more spar caps, or similar.

In another aspect, the present disclosure is directed to a method formanufacturing at least a portion of a rotor blade of a wind turbine. Themethod includes forming a rotor blade structure having a first surfaceand an opposing, second surface, the first and second surfaces beingsubstantially flat. Further, the method includes printing, via a CNCdevice, at least one of a leading edge segment of the rotor blade or atrailing edge segment of the rotor blade onto one of the first or secondsurfaces, wherein the printed segment bonds to the first or secondsurface as segment is being deposited. Moreover, the method includessecuring the other of the leading edge segment or the trailing edgesegment to the opposing first or second surface so as to complete therotor blade.

In yet another aspect, the present disclosure is directed to a rotorblade of a wind turbine. The rotor blade includes a rotor bladestructure having a box configuration with opposing spar caps andparallel shear web members. The parallel shear web members define afirst surface and an opposing, second surface, the first and secondsurfaces being substantially flat. Further, the rotor blade includes aprinted leading edge segment bonded to the first surface of the parallelshear web members and a printed trailing edge segment bonded onto thesecond surface of the parallel shear web members. In addition, theleading and trailing edge segments are constructed of a fiber-reinforcedthermoplastic or thermoset material. The rotor blade also includes oneor more continuous, multi-axial fiber-reinforced outer skins secured tothe printed leading and trailing edge segments.

In one embodiment, the shear web is constructed of one or more sandwichpanels having a core material surrounded by one or more fiber-reinforcedouter skins. In another embodiment, the spar cap(s) may be constructedof pultruded members. In further embodiments, the fiber-reinforcedthermoplastic outer skin(s) may include pressure and suction side skins,a split trailing edge skin, leading and trailing edge segment skins, orcombinations thereof. It should also be understood that the rotor blademay further include additional features as described herein.

In yet another aspect, the present disclosure is directed to a methodfor manufacturing a rotor blade panel of a wind turbine. The methodincludes forming an outer surface of the rotor blade panel from one ormore fiber-reinforced outer skins. The method also includes printing,via a CNC device, at least one 3-D reinforcement structure onto an innersurface of the one or more fiber-reinforced outer skins to form therotor blade panel. Thus, the reinforcement structure bonds to the one ormore fiber-reinforced outer skins as the reinforcement structure isbeing deposited.

In one embodiment, the fiber-reinforced outer skins or the reinforcementstructure may be constructed of a thermoplastic material or a thermosetmaterial. More specifically, the fiber-reinforced outer skins or thereinforcement structure may include a thermoplastic polymer, a thermosetpolymer, a thermoplastic foam, or a thermoset foam. In anotherembodiment, the reinforcement structure may include a fiber material,including but not limited to glass fibers, nanofibers, carbon fibers,metal fibers, wood fibers, bamboo fibers, polymer fibers, or ceramicfibers, or similar.

In further embodiments, the rotor blade panel may include a pressureside surface, a suction side surface, a trailing edge segment, a leadingedge segment, or combinations thereof.

In additional embodiments, the CNC device deposits the reinforcementstructure along a contour of the inner surface of the one or more fiberreinforced outer skins.

In yet another embodiment, the method includes printing and depositing,via the CNC device, one or more aerodynamic surface features to an outersurface of the one or more fiber reinforced outer skins. Morespecifically, in such embodiments, the aerodynamic feature(s) mayinclude vortex generators, chord extensions, serrations, gurney flaps,flow anchors, tip extensions, winglets, or similar.

In still further embodiments, the method may also include forming theone or more fiber-reinforced outer skins via at least one of injectionmolding, 3-D printing, two-dimensional (2-D) pultrusion, 3-D pultrusion,thermoforming, vacuum forming, pressure forming, bladder forming,automated fiber deposition, automated fiber tape deposition, or vacuuminfusion.

In another embodiment, the step of forming the outer surface of therotor blade panel from one or more fiber-reinforced outer skins mayinclude providing one or more generally flat fiber-reinforced outerskins, forcing the one or more fiber-reinforced outer skins into adesired shape corresponding to a contour of the outer surface of therotor blade, and maintaining the one or more fiber-reinforced outerskins in the desired shape during printing and depositing such that whenthe one or more fiber-reinforced outer skins with the reinforcementstructure printed thereto is released, the outer skins generally retainthe desired shape. In certain embodiments, the fiber-reinforced outerskins are forced into and maintained in the desired shape duringprinting and depositing via a tooling device. More specifically, inparticular embodiments, the tooling device may include vacuum, one ormore magnets, one or more mechanical devices, one or more adhesives, aheating system, a cooling system, or any combination thereof.

In one embodiment, the method may further include treating the innersurface of the one or more fiber-reinforced outer skins to promotebonding between the one or more fiber-reinforced outer skins and thereinforcement structure. More specifically, in certain embodiments, thestep of treating the inner surface may include flame treating, plasmatreating, chemical treating, chemical etching, mechanical abrading,embossing, elevating a temperature of at least areas to be printed onthe one or more fiber reinforced outer skins, and/or any other suitabletreatment method to promote said bonding. In additional embodiments, themethod may include forming the one or more fiber-reinforced outer skinswith more (or even less) matrix resin material on the inside surface topromote said bonding.

In still further embodiments, the method may include printing, via theCNC device, one or more structural components at one or more locationsof the assembled rotor blade containing a gap. More specifically, incertain embodiments, the one or more locations may include a leadingedge, a trailing edge, one or more spar caps, or a shear web. Forexample, in particular embodiments, after the rotor blade has beenassembled, one or more gaps may exist between installed components, e.g.the installed spar cap installed or when the rotor blade is closed). Insuch instances, the structural components are configured to fill thegap.

In yet another embodiment, the method may include securing one or morefiber-reinforced inner skins to the rotor blade panel.

In particular embodiments, the method may also include printing, via theCNC device, one or more additional features directly to the rotor bladepanel, wherein heat from the printing bonds the additional features tothe rotor blade panel. In such embodiments, the additional feature(s)may include a spar cap, a shear web, a structural shear clip, alightning cable connection guide, a lightning cable cover, a gussetfeature, a landing interface, or a trough for one or more spar caps.

It should also be understood that the method may further include any ofthe additional steps and/or features as described herein.

In still another aspect, the present disclosure is directed to a rotorblade panel for a rotor blade of a wind turbine. The rotor blade panelincludes an outer surface formed from one or more continuous,multi-axial fiber-reinforced thermoplastic or thermoset outer skins anda three-dimensional (3-D) printed reinforcement structure welded onto aninner surface of the one or more fiber-reinforced thermoplastic outerskins. Further, the reinforcement structure is constructed of afiber-reinforced thermoplastic or thermoset material.

In one embodiment, the outer surface may correspond to a pressure sidesurface of the rotor blade, a suction side surface of the rotor blade, atrailing edge segment of the rotor blade, a leading edge segment of therotor blade, or combinations thereof.

It should also be understood that the rotor blade panel may furtherinclude any of the additional steps and/or features as described herein.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 illustrates a perspective view of one embodiment of a windturbine according to the present disclosure;

FIG. 2 illustrates a perspective view of one embodiment of a rotor bladeof a wind turbine according to the present disclosure;

FIG. 3 illustrates an exploded view of the modular rotor blade of FIG.2;

FIG. 4 illustrates a cross-sectional view of one embodiment of a leadingedge segment of a modular rotor blade according to the presentdisclosure;

FIG. 5 illustrates a cross-sectional view of one embodiment of atrailing edge segment of a modular rotor blade according to the presentdisclosure;

FIG. 6 illustrates a cross-sectional view of the modular rotor blade ofFIG. 2 according to the present disclosure along line 6-6;

FIG. 7 illustrates a cross-sectional view of the modular rotor blade ofFIG. 2 according to the present disclosure along line 7-7;

FIG. 8 illustrates a cross-sectional view of one embodiment of a rotorblade structure according to the present disclosure, particularlyillustrating a rotor blade structure having a box configuration;

FIG. 9 illustrates a cross-sectional view of one embodiment of a rotorblade structure having a leading edge segment of the rotor blade printedthereto according to the present disclosure;

FIG. 10 illustrates a detailed, cross-sectional view of FIG. 9;

FIG. 11 illustrates a cross-sectional view of one embodiment of a rotorblade having leading and trailing edge segments of the rotor bladeprinted to a rotor blade structure according to the present disclosure;

FIG. 12 illustrates a detailed, cross-sectional view of FIG. 11;

FIG. 13 illustrates a cross-sectional view of another embodiment of arotor blade according to the present disclosure, particularlyillustrating leading and trailing edge outer skins secured to leadingand trailing edge segments of the rotor blade;

FIG. 14 illustrates a cross-sectional view of still another embodimentof a rotor blade according to the present disclosure, particularlyillustrating a plurality of structural components configured at theleading and trailing edges and the spar caps of the rotor blade;

FIG. 15 illustrates a cross-sectional view of yet another embodiment ofa rotor blade according to the present disclosure, particularlyillustrating an outer skin with a split trailing edge secured to leadingand trailing edge segments of the rotor blade;

FIG. 16 illustrates a cross-sectional view of a further embodiment of arotor blade according to the present disclosure, particularlyillustrating leading and trailing edge outer skins secured to leadingand trailing edge segments of the rotor blade, wherein the trailing edgeouter skin has a split trailing edge;

FIG. 17 illustrates a cross-sectional view of one embodiment of a rotorblade according to the present disclosure, particularly illustratinginner skins welded to a rotor blade structure of the rotor blade;

FIG. 18 illustrates a cross-sectional view of another embodiment of arotor blade according to the present disclosure, particularlyillustrating a rotor blade structure of the rotor blade having an I-beamconfiguration;

FIG. 19 illustrates a partial cross-sectional view of one embodiment ofa trailing edge segment of a rotor blade according to the presentdisclosure, particularly illustrating a rotor blade structure having anI-beam configuration with slots configured to receive spar caps therein;

FIG. 20 illustrates a partial cross-sectional view of another embodimentof a trailing edge segment of a rotor blade according to the presentdisclosure, particularly illustrating a rotor blade structure having anI-beam configuration and having spar caps configured within slots of therotor blade structure;

FIG. 21 illustrates a perspective view of one embodiment of a shear webthat has been printed onto a sandwich panel according to the presentdisclosure;

FIG. 22 illustrates a perspective view of one embodiment of a shear webconfigured on a fourth axis of a CNC device, such as a 3-D printer,according to the present disclosure;

FIG. 23 illustrates a cross-sectional view of one embodiment of a shearweb that has been printed onto a sandwich panel according to the presentdisclosure, particularly illustrating additional features that have beenprinted to the shear web;

FIG. 24 illustrates a perspective view of another embodiment of a shearweb that has been printed onto a sandwich panel according to the presentdisclosure, particularly illustrating additional features that have beenprinted to the shear web; and

FIG. 25 illustrates a schematic diagram of one embodiment of a printedrotor blade panel according to the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Generally, the present disclosure is directed to methods formanufacturing wind turbine rotor blades and components thereof usingautomated deposition of materials via technologies such as 3-D Printing,additive manufacturing, automated fiber deposition, as well as othertechniques that utilize CNC control and multiple degrees of freedom todeposit material. Thus, the methods described herein provide manyadvantages not present in the prior art. For example, the methods of thepresent disclosure provide the ability to easily customize bladestructures having various curvatures, aerodynamic characteristics,strengths, stiffness, etc. As such, the printed structures of thepresent disclosure can be designed to match the stiffness and/orbuckling resistance of existing sandwich panels rotor blades. Morespecifically, the printed structures typically contain hollowstructures, which allow the printed structures to be less limited inheight because the structures are not completely filled with foam andinfusion resin, which is typical for conventional sandwich panels. Assuch, the rotor blades and components thereof of the present disclosurecan be more easily customized based on the local buckling resistanceneeded. For example, if there is an area of high buckling in thestructural analysis, the rib and/or stringer structure of the rotorblade can be printed in a tighter pattern or taller pattern or both toalleviate the area of concern, while using a more open or shorterstructure in areas of reduced buckling issues. Further, if desirable,the structure can be built to connect or abut against a structure on theopposite side of the rotor blade in select areas. As such, the methodsof the present disclosure are also useful for intentionally allowingless buckling resistance in the rotor blades in select areas to allowbuckling during extreme gust events to promote load shedding.

In addition, the methods of the present disclosure provide a high levelof automation, faster throughput, and reduced tooling costs and/orhigher tooling utilization. Further, the rotor blades of the presentdisclosure may not require adhesives, especially those produced withthermoplastic materials, thereby eliminating cost, quality issues, andextra weight associated with bond paste.

Referring now to the drawings, FIG. 1 illustrates one embodiment of awind turbine 10 according to the present disclosure. As shown, the windturbine 10 includes a tower 12 with a nacelle 14 mounted thereon. Aplurality of rotor blades 16 are mounted to a rotor hub 18, which is inturn connected to a main flange that turns a main rotor shaft. The windturbine power generation and control components are housed within thenacelle 14. The view of FIG. 1 is provided for illustrative purposesonly to place the present invention in an exemplary field of use. Itshould be appreciated that the invention is not limited to anyparticular type of wind turbine configuration. In addition, the presentinvention is not limited to use with wind turbines, but may be utilizedin any application having rotor blades.

Referring now to FIGS. 2 and 3, various views of a rotor blade 16according to the present disclosure are illustrated. As shown, theillustrated rotor blade 16 has a segmented or modular configuration. Itshould also be understood that the rotor blade 16 may include any othersuitable configuration now known or later developed in the art. Asshown, the modular rotor blade 16 includes a main blade structure 15constructed, at least in part, from a thermoset and/or a thermoplasticmaterial and at least one blade segment 21 configured with the mainblade structure 15. More specifically, as shown, the rotor blade 16includes a plurality of blade segments 21. The blade segment(s) 21 mayalso be constructed, at least in part, from a thermoset and/or athermoplastic material.

The thermoplastic rotor blade components and/or materials as describedherein generally encompass a plastic material or polymer that isreversible in nature. For example, thermoplastic materials typicallybecome pliable or moldable when heated to a certain temperature andreturns to a more rigid state upon cooling. Further, thermoplasticmaterials may include amorphous thermoplastic materials and/orsemi-crystalline thermoplastic materials. For example, some amorphousthermoplastic materials may generally include, but are not limited to,styrenes, vinyls, cellulosics, polyesters, acrylics, polysulphones,and/or imides. More specifically, exemplary amorphous thermoplasticmaterials may include polystyrene, acrylonitrile butadiene styrene(ABS), polymethyl methacrylate (PMMA), glycolised polyethyleneterephthalate (PET-G), polycarbonate, polyvinyl acetate, amorphouspolyamide, polyvinyl chlorides (PVC), polyvinylidene chloride,polyurethane, or any other suitable amorphous thermoplastic material. Inaddition, exemplary semi-crystalline thermoplastic materials maygenerally include, but are not limited to polyolefins, polyamides,fluropolymer, ethyl-methyl acrylate, polyesters, polycarbonates, and/oracetals. More specifically, exemplary semi-crystalline thermoplasticmaterials may include polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polypropylene, polyphenyl sulfide, polyethylene,polyamide (nylon), polyetherketone, or any other suitablesemi-crystalline thermoplastic material.

Further, the thermoset components and/or materials as described hereingenerally encompass a plastic material or polymer that is non-reversiblein nature. For example, thermoset materials, once cured, cannot beeasily remolded or returned to a liquid state. As such, after initialforming, thermoset materials are generally resistant to heat, corrosion,and/or creep. Example thermoset materials may generally include, but arenot limited to, some polyesters, some polyurethanes, esters, epoxies, orany other suitable thermoset material.

In addition, as mentioned, the thermoplastic and/or the thermosetmaterial as described herein may optionally be reinforced with a fibermaterial, including but not limited to glass fibers, carbon fibers,polymer fibers, wood fibers, bamboo fibers, ceramic fibers, nanofibers,metal fibers, or similar or combinations thereof. In addition, thedirection of the fibers may include multi-axial, unidirectional,biaxial, triaxial, or any other another suitable direction and/orcombinations thereof. Further, the fiber content may vary depending onthe stiffness required in the corresponding blade component, the regionor location of the blade component in the rotor blade 16, and/or thedesired weldability of the component.

More specifically, as shown, the main blade structure 15 may include anyone of or a combination of the following: a pre-formed blade rootsection 20, a pre-formed blade tip section 22, one or more one or morecontinuous spar caps 48, 50, 51, 53, one or more shear webs 35 (FIGS.6-7), an additional structural component 52 secured to the blade rootsection 20, and/or any other suitable structural component of the rotorblade 16. Further, the blade root section 20 is configured to be mountedor otherwise secured to the rotor 18 (FIG. 1). In addition, as shown inFIG. 2, the rotor blade 16 defines a span 23 that is equal to the totallength between the blade root section 20 and the blade tip section 22.As shown in FIGS. 2 and 6, the rotor blade 16 also defines a chord 25that is equal to the total length between a leading edge 24 of the rotorblade 16 and a trailing edge 26 of the rotor blade 16. As is generallyunderstood, the chord 25 may generally vary in length with respect tothe span 23 as the rotor blade 16 extends from the blade root section 20to the blade tip section 22.

Referring particularly to FIGS. 2-7, any number of blade segments 21having any suitable size and/or shape may be generally arranged betweenthe blade root section 20 and the blade tip section 22 along alongitudinal axis 27 in a generally span-wise direction. Thus, the bladesegments 21 generally serve as the outer casing/covering of the rotorblade 16 and may define a substantially aerodynamic profile, such as bydefining a symmetrical or cambered airfoil-shaped cross-section. Inadditional embodiments, it should be understood that the blade segmentportion of the blade 16 may include any combination of the segmentsdescribed herein and are not limited to the embodiment as depicted. Inaddition, the blade segments 21 may be constructed of any suitablematerials, including but not limited to a thermoset material or athermoplastic material optionally reinforced with one or more fibermaterials. More specifically, in certain embodiments, the blade segments21 may include any one of or combination of the following bladesegments: pressure and/or suction side segments 44, 46, (FIGS. 2 and 3),leading and/or trailing edge segments 40, 42 (FIGS. 2-6), a non-jointedsegment, a single-jointed segment, a multi-jointed blade segment, aJ-shaped blade segment, or similar.

More specifically, as shown in FIG. 4, the leading edge segments 40 mayhave a forward pressure side surface 28 and a forward suction sidesurface 30. Similarly, as shown in FIG. 5, each of the trailing edgesegments 42 may have an aft pressure side surface 32 and an aft suctionside surface 34. Thus, the forward pressure side surface 28 of theleading edge segment 40 and the aft pressure side surface 32 of thetrailing edge segment 42 generally define a pressure side surface of therotor blade 16. Similarly, the forward suction side surface 30 of theleading edge segment 40 and the aft suction side surface 34 of thetrailing edge segment 42 generally define a suction side surface of therotor blade 16. In addition, as particularly shown in FIG. 6, theleading edge segment(s) 40 and the trailing edge segment(s) 42 may bejoined at a pressure side seam 36 and a suction side seam 38. Forexample, the blade segments 40, 42 may be configured to overlap at thepressure side seam 36 and/or the suction side seam 38. Further, as shownin FIG. 2, adjacent blade segments 21 may be configured to overlap at aseam 54. Thus, where the blade segments 21 are constructed at leastpartially of a thermoplastic material, adjacent blade segments 21 can bewelded together along the seams 36, 38, 54, which will be discussed inmore detail herein. Alternatively, in certain embodiments, the varioussegments of the rotor blade 16 may be secured together via an adhesive(or mechanical fasteners) configured between the overlapping leading andtrailing edge segments 40, 42 and/or the overlapping adjacent leading ortrailing edge segments 40, 42.

In specific embodiments, as shown in FIGS. 2-3 and 6-7, the blade rootsection 20 may include one or more longitudinally extending spar caps48, 50 infused therewith. For example, the blade root section 20 may beconfigured according to U.S. application Ser. No. 14/753,155 filed Jun.29, 2015 entitled “Blade Root Section for a Modular Rotor Blade andMethod of Manufacturing Same” which is incorporated herein by referencein its entirety.

Similarly, the blade tip section 22 may include one or morelongitudinally extending spar caps 51, 53 infused therewith. Morespecifically, as shown, the spar caps 48, 50, 51, 53 may be configuredto be engaged against opposing inner surfaces of the blade segments 21of the rotor blade 16. Further, the blade root spar caps 48, 50 may beconfigured to align with the blade tip spar caps 51, 53. Thus, the sparcaps 48, 50, 51, 53 may generally be designed to control the bendingstresses and/or other loads acting on the rotor blade 16 in a generallyspan-wise direction (a direction parallel to the span 23 of the rotorblade 16) during operation of a wind turbine 10. In addition, the sparcaps 48, 50, 51, 53 may be designed to withstand the span-wisecompression occurring during operation of the wind turbine 10. Further,the spar cap(s) 48, 50, 51, 53 may be configured to extend from theblade root section 20 to the blade tip section 22 or a portion thereof.Thus, in certain embodiments, the blade root section 20 and the bladetip section 22 may be joined together via their respective spar caps 48,50, 51, 53.

In addition, the spar caps 48, 50, 51, 53 may be constructed of anysuitable materials, e.g. a thermoplastic or thermoset material orcombinations thereof. Further, the spar caps 48, 50, 51, 53 may bepultruded from thermoplastic or thermoset resins. As used herein, theterms “pultruded,” “pultrusions,” or similar generally encompassreinforced materials (e.g. fibers or woven or braided strands) that areimpregnated with a resin and pulled through a stationary die such thatthe resin cures or undergoes polymerization. As such, the process ofmanufacturing pultruded members is typically characterized by acontinuous process of composite materials that produces composite partshaving a constant cross-section. Thus, the pre-cured composite materialsmay include pultrusions constructed of reinforced thermoset orthermoplastic materials. Further, the spar caps 48, 50, 51, 53 may beformed of the same pre-cured composites or different pre-curedcomposites. In addition, the pultruded components may be produced fromrovings, which generally encompass long and narrow bundles of fibersthat are not combined until joined by a cured resin.

Referring to FIGS. 6-7, one or more shear webs 35 may be configuredbetween the one or more spar caps 48, 50, 51, 53. More particularly, theshear web(s) 35 may be configured to increase the rigidity in the bladeroot section 20 and/or the blade tip section 22. Further, the shearweb(s) 35 may be configured to close out the blade root section 20.

In addition, as shown in FIGS. 2 and 3, the additional structuralcomponent 52 may be secured to the blade root section 20 and extend in agenerally span-wise direction. For example, the structural component 52may be configured according to U.S. application Ser. No. 14/753,150filed Jun. 29, 2015 entitled “Structural Component for a Modular RotorBlade” which is incorporated herein by reference in its entirety. Morespecifically, the structural component 52 may extend any suitabledistance between the blade root section 20 and the blade tip section 22.Thus, the structural component 52 is configured to provide additionalstructural support for the rotor blade 16 as well as an optionalmounting structure for the various blade segments 21 as describedherein. For example, in certain embodiments, the structural component 52may be secured to the blade root section 20 and may extend apredetermined span-wise distance such that the leading and/or trailingedge segments 40, 42 can be mounted thereto.

Referring now to FIGS. 8-25, the present disclosure is directed tomethods for manufacturing a rotor blade of a wind turbine, such as therotor blade 16 illustrated in FIGS. 2 and 3 via 3-D printing. 3-Dprinting, as used herein, is generally understood to encompass processesused to synthesize three-dimensional objects in which successive layersof material are formed under computer control to create the objects. Assuch, objects of almost any size and/or shape can be produced fromdigital model data. It should further be understood that the methods ofthe present disclosure are not limited to 3-D printing, but rather, mayalso encompass more than three degrees of freedom such that the printingtechniques are not limited to printing stacked two-dimensional layers,but are also capable of printing curved shapes.

Referring particularly to FIG. 8, one embodiment of the method includesforming a rotor blade structure 56 having a first surface 58 and anopposing, second surface 60. Further, as shown, the first and secondsurfaces 58, 60 are substantially flat. For example, as shown, the rotorblade structure 56 may include a shear web 35 or one or more spar caps48, 50, 51, 53. More specifically, as shown in the illustratedembodiment, the shear web 35 may include parallel shear web members 39.Further, in certain embodiments, each of the parallel shear web members39 may be formed from one or more sandwich panels having a core material62 surrounded by one or more fiber-reinforced thermoplastic or thermosetouter skins 64. In certain embodiments, the sandwich panels may bepultruded. Further, in particular embodiments, the core material 62described herein may be constructed of any suitable materials, includingbut not limited to low-density foam, cork, composites, balsa wood,composites, or similar. Suitable low-density foam materials may include,but are not limited to, polystyrene foams (e.g., expanded polystyrenefoams), polyurethane foams (e.g. polyurethane closed-cell foam),polyethylene terephthalate (PET) foams, other foam rubbers/resin-basedfoams and various other open cell and closed cell foams.

In addition, as shown in FIGS. 8-17, the shear web 35 and the one ormore spar caps 48, 50, 51, 53 may define a box configuration, i.e.having a square or rectangular cross-section. Thus, as shown, the boxconfiguration define the first and second surfaces 58, 60 that provideideal printing surfaces for three-dimensionally printing the leading andtrailing edge segments 40, 42 of the rotor blade 16, which is discussedin more detail below.

In alternative embodiments, as shown in FIGS. 21 and 22, the step offorming the rotor blade structure 56 may include machining, e.g. via CNCmachining, water-jet cutting, or laser-jet cutting a profile of theshear web 35 into the sandwich panel. In such embodiments, as shown inFIGS. 18-20, rather than the rotor blade structure 56 having a boxconfiguration, the structure 56 may have an I-beam configuration with asingle shear web 35 and two opposing spar caps 48, 50 as mentionedabove. Thus, as shown in FIGS. 19 and 20, the method may further includeforming one or more slots 66 in the rotor blade structure 56, theleading edge segments 40, and/or the trailing edge segment 42 of therotor blade 16. Each of the spar caps 48, 50 can then be easily insertedinto one of the slots 66 and secured therein. For example, in certainembodiments, the spar caps 48, 50 may be secured into the slots 66 viaat least one of adhesives, fasteners, or welding.

Referring now to FIGS. 9 and 10, the method further includes printing,via a CNC device, a leading edge segment 40 of the rotor blade 16 ontothe first surface 58, wherein the leading edge segment 40 bonds to thefirst surface 58 as the leading edge segment 40 is being deposited. Itshould be understood that the leading edge segment 40 may have anysuitable configuration. For example, as shown, the leading edge segment40 of the rotor blade 16 may constructed of a plurality of ribs and/orstringers. Further, the leading edge segment 40 may be constructed of athermoplastic or thermoset fiber-reinforced resin, such as PETG or epoxyand may include short, long and/or continuous fiber materials, such asglass fibers or any suitable fibers described herein. In additionalembodiments, structural reinforcements may be added to the leading edgesegment 40 during the printing process.

Referring now to FIGS. 11 and 12, the method may also include rotatingthe rotor blade structure 56 having the leading edge segment 40 attachedthereto. More specifically, in certain embodiments, the step of rotatingthe rotor blade structure 56 having the leading edge segment 40 attachedthereto may include utilizing a fourth axis 82 (FIG. 22) configured inthe CNC device 80 that rotates the rotor blade structure 56 after theleading edge segment 40 has been printed on the first surface 58. Assuch, the method may also include printing, via the CNC device 80, atrailing edge segment 42 of the rotor blade 16 onto the second surface60, wherein the trailing edge segment 42 bonds to the second surface 60as the trailing edge segment 42 is being deposited. The trailing edgesegment 42 of the rotor blade 16 may also be constructed of any suitablethermoplastic or thermoset fiber-reinforced resin.

Referring now to FIGS. 13-18, the method also includes securing one ormore fiber-reinforced thermoplastic or thermoset outer skins 64 to theprinted leading and trailing edge segments 40, 42 so as to complete therotor blade 16. More specifically, in certain embodiments, the step ofsecuring the fiber-reinforced outer skin(s) 64 to the leading andtrailing edge segments 40, 42 so as to complete the rotor blade 16 mayinclude bonding or welding the fiber-reinforced outer skin(s) 64 to theleading and trailing edges 40, 42. In further embodiments, the outerskin(s) 64 may include pressure and suction side skins, a split trailingedge skin, leading and trailing edge skins, or combinations thereof. Forexample, as shown in FIG. 13, the outer skin(s) 64 may include a leadingedge outer skin and a trailing edge outer skin. As shown in FIG. 14, theouter skin(s) 64 include two leading edge outer skins and a singletrailing edge outer skin. As shown in FIG. 15, the outer skin(s) 64include a single outer skin having a split trailing edge. As shown inFIG. 16, the outer skin(s) 64 include a single leading edge outer skinand two trailing edge outer skins. As shown in FIG. 17, the outerskin(s) 64 include two trailing edge outer skins and two leading edgeouter skins.

In addition, in certain embodiments, the outer skin(s) 64 may includecontinuous multi-axial fibers, such as biaxial fibers. Further, inparticular embodiments, the method may include forming the outer skin(s)64 via at least one of injection molding, 3-D printing, 2-D pultrusion,3-D pultrusion, thermoforming, vacuum forming, pressure forming, bladderforming, automated fiber deposition, automated fiber tape deposition, orvacuum infusion.

Referring particularly to FIG. 14, the method may further includeprinting, via the CNC device, one or more structural components 68 (e.g.continuous, unidirectional fibers) at one or more locations of the rotorblade 16 containing a gap, e.g. between the printed leading and trailingedge segments 40, 42 and the outer skin(s) 64. More specifically, asshown, the location(s) may include the leading edge segment 40, thetrailing edge segment 42, or the spar caps 48, 50 of the rotor blade 16.In such embodiments, the unidirectional fibers do not run parallel tothe build plane due to blade pre-bend, twist, etc.

Referring to FIG. 17, the method may also include securing one or morefiber-reinforced thermoplastic or thermoset inner skins 70 to the rotorblade structure 56. For example, as shown, the inner skins 70 may bewelded to the rotor blade structure 56. As such, the inner skins 70 areconfigured to provide additional structural support to the rotor blade16.

Referring now to FIGS. 23 and 24, the method may also include printing,via the CNC device, one or more additional features 72 directly to therotor blade structure 56 and/or to an outer surface of the outer skins64, wherein heat from the printing bonds the additional features 72 tothe rotor blade structure 56. More specifically, as shown, theadditional feature(s) 72 may be printed to the rotor blade structure 56and may include a structural shear clip, a lightning cable connectionguide, a lightning cable cover, a gusset feature, a landing interface, atrough for the one or more spar caps, or similar. In additionalembodiments, the additional feature(s) 72 may be printed to the outersurface of the outer skins 64 and may include vortex generators, chordextensions, serrations, gurney flaps, flow anchors, tip extensions,winglets, or similar. As such, the methods of the present disclosure caneasily print/deposit rotor blade features within the rotor blade or onan exterior of the rotor blade using the same printing techniques.

Referring now to FIG. 25, the present disclosure is also directed to amethod for manufacturing a rotor blade panel 74 of a wind turbine, e.g.such as the blade segments illustrated in FIGS. 2-7. As such, in certainembodiments, the rotor blade panel 74 (i.e. the outer surface 76thereof) may include a pressure side surface, a suction side surface, atrailing edge segment, a leading edge segment, or combinations thereof.More specifically, as shown in FIG. 25, the method includes forming anouter surface 76 of the rotor blade panel 74 from one or more of thefiber-reinforced outer skins 64 described herein. Further, as mentioned,the fiber-reinforced outer skins 64 may include one or more continuous,multi-axial (e.g. biaxial) fiber-reinforced thermoplastic or thermosetouter skins. In addition, as shown, the outer surface 76 of the rotorblade panel 74 may be curved. As such, the CNC device may be adapted toinclude a tooling path that follows a contour of the curved outersurface 76 of the rotor blade panel 74. As such, the CNC device isconfigured to print and deposit 3-D reinforcement structure 78 onto anouter surface of the one or more fiber-reinforced outer skins to formthe rotor blade panel 74. Thus, the reinforcement structure bonds to theone or more fiber-reinforced outer skins as the reinforcement structureis being deposited. As such, suitable materials for the printedreinforcement 78 and the outer skins 64 are chosen such that the printedreinforcement 78 bonds to the outer skins 64 during deposition.

More specifically, in certain embodiments, the step of forming the outersurface 76 of the rotor blade panel 74 from one or more fiber-reinforcedouter skins 64 may include providing one or more generally flatfiber-reinforced outer skins, forcing the outer skins 64 into a desiredshape corresponding to a contour of the outer surface 76 of the rotorblade 16, and maintaining the outer skins 64 in the desired shape duringprinting and depositing. As such, the outer skins 64 generally retaintheir desired shape when the outer skins 64 and the reinforcementstructure printed thereto are released.

In certain embodiments, the outer skins 64 may be forced into andmaintained in the desired shape during printing and depositing via atooling device 84. For example, in particular embodiments, the toolingdevice 84 may include vacuum, one or more magnets, one or moremechanical devices, one or more adhesives, a heating system, a coolingsystem, or any combination thereof.

In another embodiment, the method may further include treating the innersurface 86 of the outer skins 64 to promote bonding between the outerskins 64 and the reinforcement structure 78. More specifically, incertain embodiments, the step of treating the inner surface 76 mayinclude flame treating, plasma treating, chemical treating, chemicaletching, mechanical abrading, embossing, elevating a temperature of atleast areas to be printed on the outer skins 64, and/or any othersuitable treatment method to promote said bonding. In additionalembodiments, the method may include forming the outer skins 64 with more(or even less) matrix resin material on the inside surface to promotesaid bonding.

In additional embodiments, the method may include varying the outer skinthickness and/or fiber content, as well as the fiber orientation.Further, the method may include varying the design of the printed ribsand/or stringer structures (e.g. width, height, etc.). For example, inone embodiment, the method may include printing taller reinforcementstructures for the pressure side that bond (or abut against) tallerstructures of the suction side to create additional auxiliary type shearwebs/spars depending on the design need.

In additional embodiments, the method may also include printing one ormore features at the trailing and/or leading edges of the rotor bladepanels that are configured to overlap, e.g. such as interlocking edgesor snap fits. Further, the method may include printing the rotor bladepanels to include features configured to align the spar caps therein.

The present disclosure is further directed to a method for manufacturingat least a portion of a rotor blade of a wind turbine, such as the rotorblade 16 of FIG. 2. In such an embodiment, the method includes forming arotor blade structure 56 having a first surface 58 and an opposing,second surface 60, with the first and second surfaces beingsubstantially flat as shown in FIG. 8. Further, the method includesprinting, via a CNC device, a leading edge segment 40 of the rotor blade16 or a trailing edge segment 42 of the rotor blade 16 onto one of thefirst or second surfaces 58, 60, wherein the printed segment bonds tothe first or second surface as segment is being deposited. Moreover, themethod also includes securing the other of the leading edge segment 40or the trailing edge segment 42 to the rotor blade structure 56.

For example, in one embodiment, the leading edge segment 40 may beprinted onto the first surface 58. The trailing edge segment 42 may thenbe formed using the method described with respect to FIG. 25 (i.e.forming an outer surface 76 of the rotor blade panel 74 from one or moreof the fiber-reinforced outer skins 64 and then printing and depositinga 3-D reinforcement structure 78 onto an outer surface of the one ormore fiber-reinforced outer skins to form the rotor blade panelcorresponding to the trailing edge segment 42). As such, the trailingedge segment 42 may then be easily secured to the rotor blade structure56, e.g. using welding, fasteners, or any other suitable joining method.In still further embodiments, the method may be reversed, where thetrailing edge segment 42 is first printed onto a flat surface of therotor blade structure 56 and the leading edge segment 40 is formed usingthe method described with respect to FIG. 25 and then secured to therotor blade structure 56. In other words, any of the embodimentsdescribed herein may be combined to construct a rotor blade and itsvarious components.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

1-20. (canceled)
 21. A method for manufacturing a rotor blade panel of awind turbine, the method comprising: providing one or morefiber-reinforced outer skins constructed of a thermoplastic material ora thermoset material in a mold of the rotor blade panel; forcing the oneor more fiber-reinforced outer skins into a desired shape correspondingto a contour of an outer surface of the rotor blade panel; additivelyprinting and depositing, via an extruder of a three-dimensional (3-D)printer, liquid thermoplastic material or liquid thermoset materiallayer-by-layer onto an inner surface of the one or more fiber-reinforcedouter skins to form at least one 3-D reinforcement structure thereon,thereby forming the rotor blade panel, wherein the liquid thermoplasticmaterial or the liquid thermoset material of the reinforcement structuresolidifies and bonds to the one or more fiber-reinforced outer skins asthe reinforcement structure is being printed and deposited so as tomaintain the one or more fiber-reinforced outer skins in the desiredshape such that when the one or more fiber-reinforced outer skins withthe reinforcement structure printed thereto is released, the one or morefiber-reinforced outer skins retain the desired shape in at least areaswhere the reinforcement structure is printed.
 22. The method of claim21, wherein at least one of the one or more fiber-reinforced outer skinsor the reinforcement structure comprises a fiber material, wherein thefiber material comprises a plurality of fibers, the plurality of fiberscomprising at least one of glass fibers, nanofibers, carbon fibers,metal fibers, wood fibers, bamboo fibers, polymer fibers, or ceramicfibers
 23. The method of claim 21, wherein the rotor blade panelcomprises at least one of a pressure side surface, a suction sidesurface, a trailing edge, a leading edge, or combinations thereof. 24.The method of claim 21, further comprising printing and depositing, viathe 3-D printer, the reinforcement structure along a contour of theinner surface of the one or more fiber-reinforced outer skins.
 25. Themethod of claim 21, further comprising printing and depositing, via the3-D printer, one or more aerodynamic surface features to the outersurface of the one or more fiber-reinforced outer skins.
 26. The methodof claim 21, further comprising forming the one or more fiber-reinforcedouter skins via at least one of injection molding, three-dimensional(3-D) printing, two-dimensional (2-D) pultrusion, 3-D pultrusion,thermoforming, vacuum forming, pressure forming, bladder forming,automated fiber deposition, automated fiber tape deposition, or vacuuminfusion.
 27. The method of claim 21, further comprising treating theinner surface of the one or more fiber-reinforced outer skins to promotebonding between the one or more fiber-reinforced outer skins and thereinforcement structure.
 28. The method of claim 27, wherein treatingthe inner surface of the one or more fiber-reinforced outer skinsfurther comprises at least one of flame treating, plasma treating,chemical treating, chemical etching, mechanical abrading, embossing, orelevating a temperature of one or more areas to be printed on thefiber-reinforced outer skins.
 29. The method of claim 21, furthercomprising printing and depositing, via the 3-D printer, one or morestructural components at one or more locations on the rotor blade panel,the one or more locations comprising at least one of a leading edge, atrailing edge, one or more spar caps, or a shear web.
 30. The method ofclaim 21, further comprising securing one or more inner skins to therotor blade panel.
 31. The method of claim 21, further comprisingprinting and depositing, via the 3-D printer, one or more additionalfeatures directly to the rotor blade panel, wherein heat from theprinting and depositing bonds the one or more additional features to therotor blade panel.
 32. The method of claim 31, wherein the one or moreadditional features comprise at least one of a spar cap, a shear web, astructural shear clip, a lightning cable connection guide, a lightningcable cover, a gusset feature, a landing interface, or a trough for oneor more spar caps.
 33. The method of claim 21, further comprisingforming the one or more fiber-reinforced outer skins with one or moreareas having more matrix resin material as compared to other areas onthe inside surface thereof to promote bonding.
 34. A rotor blade panelfor a rotor blade of a wind turbine formed by a method comprising thesteps of: forcing one or more fiber-reinforced outer skins into adesired shape corresponding to a contour of an outer surface of therotor blade panel; additively printing and depositing, via an extruderof a three-dimensional (3-D) printer, liquid thermoplastic material orliquid thermoset material layer-by-layer onto an inner surface of theone or more fiber-reinforced outer skins to form at least one 3-Dreinforcement structure thereon, wherein the liquid thermoplasticmaterial or the liquid thermoset material of the at least one 3-Dreinforcement structure solidifies and bonds to the one or morefiber-reinforced outer skins as the at least one 3-D reinforcementstructure is being printed and deposited so as to maintain the one ormore fiber-reinforced outer skins in the desired shape such that whenthe one or more fiber-reinforced outer skins with the at least one 3-Dreinforcement structure printed thereto is released, the one or morefiber-reinforced outer skins retain the desired shape in at least areaswhere the at least one 3-D reinforcement structure is printed.
 35. Therotor blade panel of claim 34, wherein the one or more fiber-reinforcedouter skins further comprise one or more continuous, multi-axialfiber-reinforced outer skins.
 36. The rotor blade panel of claim 34,wherein the at least one 3-D reinforcement structure comprises one ormore discrete fibers.
 37. The rotor blade panel of claim 34, wherein therotor blade panel is free of adhesive between the one or morefiber-reinforced outer skins and the at least one 3-D reinforcementstructure.
 38. The rotor blade panel of claim 34, further comprising oneor more additional features printed directly onto the rotor blade panel,wherein heat from printing bonds the one or more additional features tothe rotor blade panel.
 39. The rotor blade panel of claim 38, whereinthe one or more additional features comprise at least one of a spar cap,a shear web, a structural shear clip, a lightning cable connectionguide, a lightning cable cover, a gusset feature, a landing interface,or a trough for one or more spar caps.
 40. The rotor blade panel ofclaim 34, wherein the one or more fiber-reinforced outer skins compriseone or more areas having more matrix resin material as compared to otherareas on the inside surface thereof to promote bonding.